tbuckley/cabot-search huggingface dataset:
EXTH-70. UTILIZING ONCOLYTIC VIROTHERAPY AS AN APPROACH TO ENHANCE NEOANTIGEN SPECIFIC IMMUNE RESPONSES IN GLIOBLASTOMA
Authors: Raziye Piranlioglu, Ryujin Ahn, Anan Islam, Michal Nowicki, Alexander Ling, Himanshu Soni, Ved V Ahuja, William F Goins, Darrell J Irvine, Forest M White, Hiroshi Nakashima, E Antonio Chiocca
Journal: Neuro-Oncology (2023)

Abstract Despite the success in treating many solid cancers, immunotherapy has not shown significant efficacy in patients with glioblastoma (GBM). The lack of tumor-infiltrating T cells recognizing tumor antigens displayed with major histocompability complex I (MHC I) is one of the reasons for GBM’s evasion from immunotherapy. Our preclinical GBM models and an ongoing clinical trial with oncolytic herpes simplex virus-1 (oHSV) at our institution (NCT03152318) demonstrated that oHSV treatment leads to an increase influx of CD8+ and CD4+ T cells into tumor. However, it remained unclear whether these T cells are specific to the tumor antigens (neoantigens) or reactive to only viral antigens. To determine whether infiltrating CD8 T cells target tumor antigens, we first performed whole-exome and RNA sequencing of CT2A, a preclinical model of GBM impervious to immunotherapies for identification of neoantigens. We screened immunogenicity of identified neoantigens by ELISPOT assay. TILs from the oHSV-treated (but not from control group) reacted to two of the neoantigens that were identified with our pipeline and this activation was similar in magnitude to the reaction to the immunodominant HSV antigen. FACS analyses of TILs seven days after virotherapy showed that oHSV-treated tumor had higher level of TILs than vehicle control tumors, a finding that mirrored what we observed in our phase 1 clinical trial with oHSV. High dose of oHSV treatment not just induces the infiltration of viral specific T cells, but infiltration of T cells targeting neoantigens that were not presented without OV infection. Phosphoproteomic analysis of bulk tumor revealed activation of key inflammatory pathways, including that of T cells receptor signaling upon virus treatment. We evaluated the efficacy of therapeutic neoantigen vaccination in combination with oncolytic intratumoral virotherapy. Survival analysis showed that combination therapy not just delays the tumor progression but also provides survival advantage compared to monotherapies.
NIMG-44. RADIOMIC FEATURES OF CONTRAST ENHANCED T1 MRI SEQUENCES PREDICT SURVIVAL IN PRIMARY GLIOBLASTOMA PATIENTS WHO UNDERWENT ADJUVANT RADIATION THERAPY
Authors: Michael Flatley, Savannah Duenweg, Samuel Bobholz, Allison Lowman, Margaret Stebbins, Aleksandra Winiarz, Biprojit Nath, Fitzgerald Kyereme, Jennifer Connelly, Dylan Coss, Mohit Agarwal, Anjishnu Banerjee, Max Krucoff, Peter LaViolette
Journal: Neuro-Oncology (2023)

Abstract PURPOSE Glioblastoma (GBM) is an aggressive primary brain tumor that is monitored through magnetic resonance imaging (MRI). Radiomic analysis offers valuable insight into better understanding the imaging features of these tumors. We tested the hypothesis that changes in radiomic features following radiation treatment predicts overall survival. Radiomic features we were interested in included 2D and 3D shape features, first order features evaluating patterns of voxel intensity within the mask regions, and higher order GLCM features. METHODS Data from 19 patients from our brain bank diagnosed with a GBM at autopsy and underwent radiation therapy were used for this study. T1C tumor masks were created by manually annotating contrast enhancing tumor for patients on pre- and post-treatment MRIs. Pyradiomics was used to extract radiomic features within both pre- and post-radiation tumor masks, including 14 shape features, 18 first order features, and 75 higher order features were compared across timepoints and the difference for each variable was correlated with overall survival. RESULTS Of the tested radiomic features, only the following shape features were found to be correlated with overall survival: Major Axis Length (R = -0.55, p =.02), Maximum 2D Diameter Row (R= -.56, p =.02), Maximum 2D Diameter Slice (R= -.52, p =.03), and Maximum 3D Diameter (R= -.47, p = .04). CONCLUSIONS These results show a decrease in the Major Axis Length, Maximum 2D Diameter, Maximum 2D Diameter, and Maximum 3D diameter of the T1C masks post-radiation correlate with an overall increase in survival. These inverse trending radiomic variables may be useful to assess tumor response to radiation therapy, specifically through assessment of shape features within the contrast-enhancing tumor region. Future research should determine how tumor changes in response to other treatment modalities and/or correlates with other prognostic variables.
DNAR-08. BASE EXCISION REPAIR AS A THERAPEUTIC TARGET FOR DIFFUSE HEMISPHERIC GLIOMA, H3.3G34-MUTANT
Authors: Alessia Portante, Laura Canty, Palak Patel, Sanja Pajovic, Monique Johnson, Byungjin Kim, Logine Negm, Jiil Chung, Sonam Dolma, Peter Dirks, Uri Tabori, Cynthia Hawkins
Journal: Neuro-Oncology (2023)

Abstract Diffuse hemispheric gliomas with H3.3G34R/V mutations are primarily found in the cerebral hemisphere in adolescents and young adults, with a median age of 16-19 years. H3.3G34R frequently co-occurs with mutations in ATRX and TP53 as well as PDGFRα. We performed mutational signature analysis on a cohort of 28 cases of Diffuse hemispheric glioma, H3G34-mutant (7 WGS and 21 WES). Mutational signatures of defects in mismatch repair (MMR), homologous recombination (HR), and nucleotide excision repair (NER) pathways were found in 86% cases whereas only two (7%) had signatures of impaired base excision repair (BER). Analysis of H3.3G34R interactome data showed loss of association with MMR, HR, and NER pathways, with gains in association with proteins in the BER pathway compared to wildtype Histone H3. We thus hypothesise the Diffuse hemispheric glioma, H3G34-mutant may be dependent on BER over other DNA damage repair pathways. To test if BER could be a therapeutic vulnerability, we knocked down integral members of the BER pathway (UNG, APEX1, MPG, and XRCC1) via shRNA in 4 patient-derived H3.3G34R-mutant cell lines (two primary and two matched recurrent), and found that knockdown of XRCC1 and MPG, led to 99% (p&amp;lt; 0.0001) and 96% (p&amp;lt; 0.0001) cell death, respectively, after 8 days, compared to scrambled control. We next tested Triptolide, a BER inhibitor, and it led to cell death in vitro with IC50s of 1.1 to 1.7 nM. Taken together, these results indicate that inhibition of the BER pathway, specifically of the scaffolding-protein XRCC1, could be used as a novel therapeutic approach for diffuse hemispheric glioma, H3.3G34-mutant.
RADT-11. THE HEMORRHAGIC RISK OF MELANOMA BRAIN METASTASES AFTER STEREOTACTIC RADIOSURGERY
Authors: Sukwoo Hong, Samantha Bouchal, Megan Bauman, Cecile Riviere-Cazaux, Andrew Pumford, Paul Brown, Elizabeth Yan, Scott Stafford, Svetomir Markovic, Michael Link, Terry Burns, Ignacio Jusue-Torres, Bruce Pollock, Ian Parney
Journal: Neuro-Oncology (2023)

Abstract OBJECTIVE This study aimed to analyze the hemorrhagic risk of melanoma brain metastases following SRS. METHODS A retrospective analysis was conducted using a prospective institutional database between 1990 and 2021. Lesional hemorrhage was categorized as definite or possible, and hemorrhage severity was graded using CTCAE. RESULTS The study identified 291 patients with 1083 lesions. The mean age of patients was 60 ± 15 years, with 61% being male. Median follow-up was 11 months, corresponding to 581 patient-years. Among the patients, 82 (28%) experienced 135 lesional hemorrhages (13%). Of these, 88 lesions in 61 patients were grade 1-2 hemorrhages, 42 lesions in 25 patients were grade 3, and five lesions in five patients progressed from grade 1 to 3. Surgical intervention was required for 17 lesions (2%) in 16 patients (5%). Lesional hemorrhage was associated with radiosurgery performed between 2015 and 2021 (OR, 0.373; 95% CI, 0.231-0.60; p &amp;lt; 0.001), increasing marginal dose (OR, 0.89; 95% CI, 0.82-0.98; p = 0.017), antiplatelet use (OR, 0.192; 95% CI, 0.082-0.45; p &amp;lt; 0.001), and WBRT (OR, 0.51; 95% CI, 0.330-0.77; p = 0.0017). The cumulative lesional hemorrhage risk reached 17–20% at 36 months following radiosurgery, with 95-96% of hemorrhages occurring within the initial year. Median OS was 11 months (95% CI, 9-13 months). Patients who received radiosurgery between 2015 and 2021 exhibited a median OS of 17 months (95% CI, 10-24 months; p &amp;lt; 0.001), while those without hemorrhage had a median OS of 12 months (95% CI, 10-14 months; p = 0.054). CONCLUSIONS Definitive hemorrhage risk was 17% for melanoma brain metastases after SRS within the first three years, with 95% of lesional hemorrhages occurring within the initial year. Surgical intervention was necessary in 5% of patients. Hemorrhage risk and overall survival improved after 2015.
EXTH-20. A MOUSE MODEL REVEALS VULNERABILITY OF IDH1-MUTATED GLIOMA TO FERROPTOSIS
Authors: Angeliki Mela, Athanassios Dovas, Aayushi Mahajan, Nelson Humala, Trang Nguyen, Smriti Kanangat, Pavan Upadhyayula, Lisa Sprinzen, Michael Argenziano, Dennis Huang, Jia Guo, Patrizia Casaccia, Markus Siegelin, Brent Stockwell, Jeffrey Bruce, Peter Canoll
Journal: Neuro-Oncology (2023)

Abstract The molecular classification of gliomas is currently based on the presence of IDH1 mutation, which is associated with better prognosis and longer survival. The hallmark of the IDH1 mutation is the production of D-2-Hydroxyglutarate with subsequent effects that are not fully understood. Ferroptosis, an iron-dependent mechanism of non-apoptotic cell death, is mostly triggered through blocking system Xc- or suppressing the antioxidant enzyme glutathione peroxidase 4 (GPX-4). In this study, we generated a mouse model of glioma harboring the IDH1(R132H) mutation in heterozygous condition, in combination with p53-deletion induced by the expression of PDGFA. We show that IDH1(R132H)-expressing mice survive longer compared to their wild-type counterparts, while histological analysis reveals characteristics of low-grade diffuse gliomas. We generated cell lines from primary tumors and analyzed their metabolic profile and response to mitochondrial stress and Ferroptosis. We treated them in vitro with RSL3, a GPX-4 inhibitor, alone or in combination with Cysteine and Methionine restriction. We show that IDH1(R132H)-expressing cells are far more sensitive to Ferroptosis in vitro. Finally, we show that convection-enhanced delivery of RSL3 in combination with dietary Cysteine and Methionine restriction in vivo, significantly prolongs survival of the IDH1(R132H)-expressing mice. Our findings suggest that Ferroptosis provides promising therapeutic potential worth exploring further and our mouse model could be used to test the efficacy of different treatments for IDH1(R132H) gliomas.
DDDR-06. THE SMOKING CESSATION AGENT LOBELINE DELAYS HYPOXIC STRESS RECOVERY RESULTING IN GLIOBLASTOMA CELL DEATH
Authors: Kathleen Attwood, Aaron Robichaud, Jae Ho Han, Gabriel Wajnberg, Jeremy Roy, Adrienne Weeks
Journal: Neuro-Oncology (2023)

Abstract Glioblastoma (GBM) is the most common and aggressive primary malignant brain tumour with a universally fatal prognosis. GBM is characterized by extensive regions of hypoxia which adversely impacts clinical outcomes, as hypoxia promotes chemoresistance. Tumour cells can adapt to and survive hypoxic stress by inducing rapid changes in the translational landscape, facilitated in part by the formation of stress granules (SGs). SGs are cytoplasmic aggregates of untranslated mRNAs and RNA binding proteins formed in response to a variety of cellular stressors, that allow cells to temporarily prioritize translation of stress-related proteins. Previous work in our laboratory has shown that GBM cells form SGs in vitro and in vivo, and that pharmacologically altering SG dynamics to prevent their dissolution (effectively locking cells in a stressed state) increases GBM cell death. Here we have identified another compound that delays the dissolution of hypoxia-induced SGs in GBM cells, the smoking cessation agent lobeline. SG dissolution typically occurs within 15 minutes post-hypoxia, however pre-treatment of immortalized GBM cells with lobeline delays SG dissolution for up to 2 hours. This delay in SG dissolution is dose dependent, as higher lobeline concentrations resulted in corresponding increases in the percentage of cells containing SGs and the average number of SGs per cell post-hypoxia. Lobeline also led to sustained phosphorylation of eIF2a (a key regulator of translation initiation) with an accompanying decrease in global protein translation levels post-hypoxia. Importantly, the combination of lobeline and hypoxia led to synergistic cell death in both immortalized and primary GBM cells, specifically through increased necrosis. Lobeline acts as a VMAT2 ligand and can stimulate dopamine release. Interestingly, we have found miRNA related to dopamine metabolism pathways overrepresented in extracellular vesicles isolated from GBM patient plasma. We postulate that disrupting the balance of stress pathways may have therapeutic potential in the future.
CNSC-17. WHOLE-BRAIN SPECTRAL CHANGE IN GLIOBLASTOMA PATIENTS: ASSOCIATIONS WITH CLINICAL COMORBIDITIES AND OVERALL SURVIVAL
Authors: Ki Yun Park, Abraham Snyder, Michael Olufawo, Gabriel Trevino, Patrick Luckett, Bidhan Lamichhane, Tao Xie, John Lee, Joshua Shimony, Eric Leuthardt
Journal: Neuro-Oncology (2023)

Abstract Glioblastoma, a highly aggressive form of brain tumor, is a brain-wide disease. We evaluated the impact of tumor burden on whole brain resting-state functional magnetic resonance imaging (rs-fMRI) activity. Specifically, we analyzed rs-fMRI signals in the temporal frequency domain in terms of the power-law exponent and fractional amplitude of low-frequency fluctuations (fALFF). We contrasted 189 patients with newly-diagnosed glioblastoma versus 189 age-matched reference participants. The patient and reference datasets were matched for age and head motion. The principal finding was markedly flatter spectra and reduced grey matter fALFF in the patients as compared to the reference dataset. We posit that the whole-brain spectral change is attributable to global dysregulation of excitatory and inhibitory balance and metabolic demand in the tumor-bearing brain. Additionally, we observed that clinical comorbidities, in particular, seizures, and MGMT promoter methylation, were associated with flatter spectra. Notably, the degree of change in spectra was predictive of overall survival. Our findings suggest that frequency domain analysis of rs-fMRI activity provides prognostic information in glioblastoma patients and offers a means of noninvasively studying the effects of glioblastoma on the whole brain.
EPID-03. SEX DIFFERENCES IN ODDS OF BRAIN METASTASIS AND OUTCOMES BY BRAIN METASTASIS STATUS AFTER ADVANCED MELANOMA DIAGNOSIS
Authors: Gino Cioffi, Mustafa Ascha, Mantas Dmukauskas, Kristin Waite, Xiaoliang Wang, Trevor Royce, Gregroy Calip, Timothy Waxweiler, Chad Rusthoven, Brian Kavanagh, Jill Barnholtz-Sloan
Journal: Neuro-Oncology (2023)

Abstract Sex differences in cancer are well-established. However, less is known about sex differences in diagnosis of brain metastasis and outcomes among individuals with advanced melanoma. Using the nationwide Flatiron Health electronic health record-derived deidentified database, we evaluated individuals diagnosed with advanced melanomafrom 1/1/11-07/30/22 who received oncologist-defined rule-based first line of therapy (N = 7,969, 33% female according to EHR, 35% w/ documentation of brain metastases). Odds of documented brain metastasis diagnosis were calculated using multivariable logistic regression adjusted for age, practice type, diagnosis period (pre/post-2017), ECOG performance status, anatomic site of melanoma, group stage, documentation of non-brain metastases prior to first-line of treatment, and BRAF positive status. Real-world overall survival (rwOS) and progression-free survival (rwPFS) starting from first-line initiation were assessed by sex, accounting for brain metastasis diagnosis as a time-varying covariate using the Cox proportional hazards model, with the same adjustments as the logistic model, excluding group stage, also adjusting for race, socioeconomic status, and insurance status. Adjusted analysis revealed males with advanced melanoma were 22% more likely to receive a brain metastasis diagnosis compared to females (aOR: 1.22, 95% CI:1.09, 1.36). Males with brain metastases had worse rwOS (aHR: 1.15, 95% CI:1.04, 1.28) but not rwPFS (aHR: 1.04, 95% CI: 0.95, 1.14) following first-line treatment initiation. Among individuals with advanced melanoma not diagnosed with brain metastases, survival was not different by sex (rwOS aHR: 1.06 [95% CI: 0.97, 1.16], rwPFS aHR: 1.02 [95% CI: 0.94, 1.1]). This study showed that males had greater odds of brain metastasis and, among those with brain metastasis poorer rwOS compared to females, while there were no sex differences in clinical outcomes for those with advanced melanoma without brain metastasis.
MODL-15. ESTABLISHMENT OF ORGANOID MODELS OF PATIENT-DERIVED GH-PRODUCING PITUITARY ADENOMA
Authors: Sachi Maeda, Fumiharu Ohka, Fumiaki Kanamori, Yuka Okumura, Kazuhito Takeuchi, Yuichi Nagata, Kazuya Motomura, Junya Yamaguchi, Yuji Kibe, Hideyuki Harada, Hiroki Shimizu, Yuhei Takido, Ryuta Saito
Journal: Neuro-Oncology (2023)

Abstract BACKGROUND Growth hormone-producing pituitary adenomas (GHomas) reveal unfavorable clinical course due to systemic complications such as excessive sweating, impaired glucose tolerance, and hypertension, in addition to its characteristic facial appearance. For GHoma, pharmacological treatments including somatostatin analogs and dopamine agonists are widely performed, however, a subset of case reveals dismal prognosis. We need to elucidate molecular mechanisms contributing to GHoma growth, however, experimental models of GHoma such as cell line and animal model are quietly limited. OBJECTIVE In recent years, organoid models using 3D-culture technologies have gained attention as useful research models for various types of cancers. This study aims to establish a novel organoid model derived from GHoma patients. Using established GHoma organoid model, we analyzed their histological characteristics. METHODS Surgical specimens from five cases of GHoma were finely dissected to approximately 1mm and embedded in Matrigel basement membrane matrix. The specimens were then cultured under 37°C conditions in a 5% CO2 incubator using a medium supplemented with various growth factors. After 28 days of culture, formalin-fixed paraffin-embedded sections were prepared, and the histological similarity with patient tumors was examined. RESULTS Hematoxylin and eosin staining showed that organoid models consisted of acidophilic, granular cytoplasm and small round nuclei, maintaining a cell morphology similar with the original tumor. Immunohistochemical staining revealed positive expression of growth hormone, Pit-1, and CAM5.2, which are specific markers for GHoma. CONCLUSIONS We successfully established a patient-derived organoid model of GHoma that retains histological and endocrinological characteristics. We believe that this model could be a valuable research model for elucidating the molecular mechanisms of GHoma and developing novel treatment approaches targeting important molecular abnormalities. Additionally, in clinical settings, this model might be useful for predicting the responsiveness to drug treatment and selecting appropriate therapies for individual patients.
DDDR-07. TARGETING THE CIRCADIAN CLOCK WITH SMALL MOLECULE COMPOUNDS RESULTS IN ANTI-TUMOR EFFECTS SPECIFICALLY IN GLIOBLASTOMA STEM CELLS
Authors: Priscilla Chan, Lian Wu, Anahit Hovsepyan, Seda Mkhitaryan, Gevorg Karapetyan, Khalid Shah, Hiroaki Wakimoto, Theodore Kamenecka, Laura Solt, Jamie Cope, Rex Moats, Tsuyoshi Hirota, Jeremy Rich, Steve Kay
Journal: Neuro-Oncology (2023)

Abstract Glioblastoma multiforme (GBM) is the most common primary brain tumor, with an average survival time of less than one year following diagnosis. Treatment success remains challenging despite aggressive, multimodal current standard-of-care consisting of maximal surgical resection followed by concurrent temozolomide (TMZ) chemotherapy and radiation. The presence of GBM stem cells (GSCs) is thought to make treatment exceptionally difficult as they are highly invasive, resistant to chemoradiation, promote angiogenesis, support an immune suppressive environment, and can recapitulate the primary tumor following surgical resection. We have reported that GSCs, however, are dependent on core circadian clock proteins, Brain and Muscle ARNTL-Like 1 (BMAL1) and Circadian Locomoter Output Cycles Protein Kaput (CLOCK), which is not observed in differentiated GBM cells or normal neuronal stem cells. In this study, we explore the anti-GSC effects of multiple families of novel small molecule circadian clock compounds that either lower BMAL1 transcription (REV-ERB agonists) or inhibit BMAL1::CLOCK heterodimer transcriptional activity (Cryptochrome (CRY) stabilizers or Casein Kinase (CK) 1/2 inhibitors). Here we report that compared to compared to non-cancerous cells, U2OS human osteosarcoma cells, and differentiated GSCs (DGCs), GSCs display increased sensitivity to clock compounds at single agent and combinatory doses of clock compounds. Additionally, clock compounds are significantly more effective in targeting GSCs than TMZ and combinations of clock compounds with TMZ can lower TMZ IC50 value in different GBM cell lines and types. Application of the CRY stabilizer SHP1705 in GBM PDX patient derived xenograft (PDX) models resulted in decreased tumor growth rate and increased survival time compared to vehicle control. These results highlight the therapeutic potential of circadian clock compounds as single agents, in combinations and as adjuvants to existing therapies by specifically targeting the GSC population in GBM.
PATH-22. CLINICAL AND MOLECULAR NEUROPATHOLOGICAL FEATURES OF EPITHELIOID GLIOBLASTOMA
Authors: Jun-ichi Adachi, Mitsuaki Shirahata, Tomonari Suzuki, Kazuhiko Mishima, Ryo Nishikawa
Journal: Neuro-Oncology (2023)

Abstract BACKGROUND Epithelioid Glioblastoma (E-GBM) has been identified as a pathological subtype of Glioblastoma. It is a rare glioblastoma and is mainly known in case reports, and the details of its clinical features and genetic characteristics are not clear. Here, we retrospecivly studied the results of clinical course and genetic features of E-GBM. METHODS Four patients who underwent surgery at our institution and were diagnosed with E-GBM were included in this study. Histological diagnosis was obtained by surgical excision in all cases. We extracted DNA from the resected tissues and analyzed glioma-related genes using various methods such as high resolution melting (HRM), MGMT methylation-specific HRM, digital PCR, and Multiple ligation-dependent probe amplification (MLPA) analysis. RESULTS E-GBM tended to develop at a slightly younger age than other general glioblastoma. All patients underwent surgical resection followed by radiation therapy and concurrent temozolomide therapy. However, none of the patients were able to transition to temozolomide maintenance therapy due to disease progression, and the overall survival period was 8 to 19 weeks, indicating an extremely poor prognosis. Genetic analysis revealed both TERT promoter mutations and BRAFV600E mutation in all cases. In addition, IDH mutation was not found, and MGMT promoter methylation was unmethylated in all cases. EGFR amplification, CDKN2A/2B homozygous deletion and 1p/19q co-deletion were not found in any cases. CONCLUSION The simultaneous mutations of TERT promoter with BRAFV600E could serve as diagnostic molecular markers for the diagnosis of E-GBM. Standard therapy for glioblastoma was not expected to be effective in treating this tumor. It was considered necessary to introduce new therapeutic strategies such as early administration of BRAF and MEK inhibitors.